From: Julian Wiedmann <jwi@linux.ibm.com>
Subject: s390/qeth: fold VLAN handling into l3_rebuild_skb()
Patch-mainline: v4.15-rc1
Git-commit: d7aa9d0bb923d55aa65a6e18428b384038c6523e
References: FATE#326350, LTC#169511, bsc#1113509

Summary:     qeth: performance improvements
Description: This adds recent functional and performance improvements for the
             qeth network driver.
             Primarily this brings Scatter-Gather support for HiperSockets,
             reduced CPU consumption in the L3 IPv4 transmit path for OSA,
             improved Promiscuous Mode performance due to IFF_UNICAST_FLT,
             support for Scatter-Gather on z/VM virtual NICs, and
             support for delayed GRO flushing.

             For sanity & stability reasons, this effectively constitutes a
             backport of the qeth device driver from 4.19 mainline.
             

Upstream-Description:

             s390/qeth: fold VLAN handling into l3_rebuild_skb()

             Move the overly complicated VLAN processing from the L3 RX handler into
             its l3_rebuild_skb() helper. No change in functionality.

             Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
             Reviewed-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
             Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/s390/net/qeth_l3_main.c |   27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1667,13 +1667,12 @@ static int qeth_l3_vlan_rx_kill_vid(stru
 	return 0;
 }
 
-static int qeth_l3_rebuild_skb(struct qeth_card *card, struct sk_buff *skb,
-			       struct qeth_hdr *hdr, unsigned short *vlan_id)
+static void qeth_l3_rebuild_skb(struct qeth_card *card, struct sk_buff *skb,
+				struct qeth_hdr *hdr)
 {
 	__u16 prot;
 	struct iphdr *ip_hdr;
 	unsigned char tg_addr[MAX_ADDR_LEN];
-	int is_vlan = 0;
 
 	if (!(hdr->hdr.l3.flags & QETH_HDR_PASSTHRU)) {
 		prot = (hdr->hdr.l3.flags & QETH_HDR_IPV6) ? ETH_P_IPV6 :
@@ -1727,11 +1726,14 @@ static int qeth_l3_rebuild_skb(struct qe
 
 	skb->protocol = eth_type_trans(skb, card->dev);
 
-	if (hdr->hdr.l3.ext_flags &
-	    (QETH_HDR_EXT_VLAN_FRAME | QETH_HDR_EXT_INCLUDE_VLAN_TAG)) {
-		*vlan_id = (hdr->hdr.l3.ext_flags & QETH_HDR_EXT_VLAN_FRAME) ?
-		 hdr->hdr.l3.vlan_id : *((u16 *)&hdr->hdr.l3.dest_addr[12]);
-		is_vlan = 1;
+	/* copy VLAN tag from hdr into skb */
+	if (!card->options.sniffer &&
+	    (hdr->hdr.l3.ext_flags & (QETH_HDR_EXT_VLAN_FRAME |
+				      QETH_HDR_EXT_INCLUDE_VLAN_TAG))) {
+		u16 tag = (hdr->hdr.l3.ext_flags & QETH_HDR_EXT_VLAN_FRAME) ?
+				hdr->hdr.l3.vlan_id :
+				*((u16 *)&hdr->hdr.l3.dest_addr[12]);
+		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), tag);
 	}
 
 	if (card->dev->features & NETIF_F_RXCSUM) {
@@ -1745,7 +1747,6 @@ static int qeth_l3_rebuild_skb(struct qe
 			skb->ip_summed = CHECKSUM_NONE;
 	} else
 		skb->ip_summed = CHECKSUM_NONE;
-	return is_vlan;
 }
 
 static int qeth_l3_process_inbound_buffer(struct qeth_card *card,
@@ -1754,8 +1755,6 @@ static int qeth_l3_process_inbound_buffe
 	int work_done = 0;
 	struct sk_buff *skb;
 	struct qeth_hdr *hdr;
-	__u16 vlan_tag = 0;
-	int is_vlan;
 	unsigned int len;
 	__u16 magic;
 
@@ -1785,12 +1784,8 @@ static int qeth_l3_process_inbound_buffe
 					card->dev->addr_len);
 				netif_receive_skb(skb);
 			} else {
-				is_vlan = qeth_l3_rebuild_skb(card, skb, hdr,
-						      &vlan_tag);
+				qeth_l3_rebuild_skb(card, skb, hdr);
 				len = skb->len;
-				if (is_vlan && !card->options.sniffer)
-					__vlan_hwaccel_put_tag(skb,
-						htons(ETH_P_8021Q), vlan_tag);
 				napi_gro_receive(&card->napi, skb);
 			}
 			break;